


Strawberry Milk

by tealmoon



Category: Undertale (Video Game)
Genre: Afterlife, Alternate Universe - Underfell, Bittersweet Ending, Body Horror, Eye Trauma, Eye socket penetration, Hurt/Comfort, Illnesses, Kissing, M/M, Oral Sex, Soul Touching, Undertale Genocide Route, Undertale Skeletons in Heat, Vaginal Fingering, Violence, discussion of skeleton pregnancy, dubious monster biology, even more dubious medical treatments, mild jealousy, no matter what happens they love each other, some gore
Language: English
Status: Completed
Published: 2017-07-17
Updated: 2018-05-20
Packaged: 2018-12-03 04:42:13
Rating: Explicit
Warnings: Graphic Depictions Of Violence, Major Character Death
Chapters: 4
Words: 15,763
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11524773
Author URL: https://archiveofourown.org/users/tealmoon/pseuds/tealmoon
Summary: It’s a new morning in the skeleton brothers’ household and time for their usual routines: getting dressed, cooking breakfast, making sure Sans doesn’t die in a terrifying and painful way.





	1. Chapter 1

The house smelled different when Sans was sick.

Papyrus was well-acquainted with all of the facets of his brother’s illness after so many years of contending with it. Luckily he properly trained Sans out of his inclination to hide it, but it was still better to head things off as fast as possible. Sans got silly ideas about being sick. He used to do absurd things like leaving the windows open or borrowing Papyrus’s cologne to mask the scent of his illness.

Of course, Papyrus marched to his room the second sleep had gotten its ungainly claws out of his skull. It didn’t matter that he was still in his pajamas! He had a brother to tend to!

Sans was already awake, which was another bad sign. He couldn’t sleep much when he was like this, or even fake it convincingly; he would squirm and kick his sheets away and turn over constantly, looking for a position that wasn’t painful. He was sitting on his mattress and staring at the wall, which Papyrus hoped meant that he had gotten at least some rest the night before. He was still in his sleep clothes with his jacket on top, the hood pulled far down over his forehead.

And there were other signs. Papyrus Checked him, to be sure, and it was as expected: his stats, aside from his HP, were all fluctuating wildly. Sometimes the numbers were so big they protruded off the screen, or they were zeroes, or negative quantities, or weird math symbols that might have made sense to Sans, if he had been coherent enough to look himself. Yes, he was definitely ill.

He didn’t look up as Papyrus sat next to him, close enough that their sides brushed. What a ridiculous, dumb-ass brother, to be so hung up about it still.

“When did it start coming on?” For Sans’s sake, he tried to keep his volume in check. He got terrible headaches when he was like this, sometimes bad enough that Papyrus would wrestle him to the ground (gently) and force painkillers past his teeth. Their supply was limited, but it was worth it not to hear Sans sobbing in pain, insisting that his skull was going to break apart.

“Last night,” Sans whispered. “Few hours after dinner.”

No wonder he had skittered off to his bedroom so soon after last night’s dinner. He held himself back from scolding about how Sans should have come to tell him immediately. Papyrus had said all of that before, and there was no point in repeating himself. Someday, he would know better.

Instead, Papyrus stood and headed to the desk. Sans had gotten everything set up, probably when it had first started coming on, before he became too incoherent with pain and pressure to remember what supplies they needed. Papyrus took the whole tray and set it down next to the mattress. He went to fill the empty bowl with warm water in the bathroom and brought a stack of towels with him. It would have been cleaner to do it in the bathroom tub, but sometimes you had to prioritize your brother’s comfort over an easy cleanup. He compensated by covering the mattress and the surrounding carpet in towels.

Sans hadn’t moved in the few minutes that took, skull still bowed, fingers still clinging to the mattress pad. (To the point that he had to bodily lift Sans to put a towel below him.) Papyrus reached out, ever mindful of his claws as he stroked his brother’s cheekbone. For once it wasn’t misted with sweat, and he couldn’t even revel in it. It was just another sign of how out of sorts Sans’s body had become.

“Sans, which eye socket is it?” Hopefully not both. That had only happened once or twice, back when Sans managed to hide it for days and it spread from one to the other, practically blinding him. It was best not to think about those days.

“Right eye,” Sans mumbled, leaning into his hand a little bit.

“How fortunate! This won’t be nearly as difficult!” Neither socket was _good_ necessarily, but the left usually developed more quickly and was more painful for Sans. “Well, go on with it. Show me.”

Papyrus liked to think he was past the urge to squeal and flinch about his brother’s condition, but seeing it never got any easier. It didn’t matter how many times Sans reassured him it wasn’t his proper eyelight, it was okay, don’t worry about it, Boss. Sans didn’t deserve something like this.

With quivering hands, Sans reached up to remove his hood, to let Papyrus see him. The whole of his eye socket had filled up with a bulging mass of red magic that twitched with every move of his skull, as if it was some sentient creature, as if it _wanted_ to grow and hurt Sans. Luckily it hadn’t gotten so far that it had started protruding out of his socket entirely, but it had progressed faster in a single night than Papyrus was comfortable with. The magical tumor was strangely icy, leeching out the warmth from Sans’s bones and the air around them.

Something had happened to Sans in those blurry early years, though Papyrus didn’t fully understand what, something that Papyrus had been too young to understand. It had been difficult enough getting to this point that he didn’t want to ruin his efforts by demanding information. But whatever it was had left Sans unable to control his own magic production.

An excess of magic had sounded lovely to Papyrus when Sans first explained it. You would never run out of energy in a battle! Imagine how many bones and blasters you could summon at once! You could render the entire population of Snowdin blue in a single go!

The reality wasn’t so fantastic. It developed on an erratic schedule; sometimes it happened once a week, and sometimes Sans managed to go months without getting sick. If there was a trigger, Papyrus hadn’t found it yet. Out of nowhere, Sans’s body would start producing far too much magic. He could teleport every five steps and fire off blasters in Snowdin Forest for minutes, and it still wouldn’t drain out.

So the magic built up, and it had to be removed. Papyrus wasn’t sure how extensive the magical excess could become, but he sometimes had nightmares about it. Sans’s teeth being pushed out of his jaw, dislodged by masses of red. Red blooming out of Sans’s joints, forcing his bones apart. A pulsing, icy growth where his beautiful core was supposed to be.

He wasn’t sure where Sans got the scalpels—maybe the Lab? He tried to keep it a secret, but Papyrus knew he spent a lot of time in that part of Hotland, with that reptile scientist Undyne sometimes gushed about. Bones were straight out, Sans told him: too hard to get them sharp or clean enough. It was worse that Papyrus knew he was talking from experience.

Papyrus helped Sans out of his jacket, making sure to toss it in the far corner where it would stay clean, and draped a towel over his shoulders to ease his shivering.

That was all the fussing he’d allow himself until it was done. It was best not to hesitate any longer, or Sans might try to do this, thinking Papyrus had lost his nerve. On the contrary, the thought steadied him. Never again would his brother have to perform shaky surgery on himself, leaning up against the bathroom mirror and dripping red into the sink. Papyrus took up the scalpel in one hand, put the other hand under Sans’s jaw to steady him, and got to work.

The sounds were the worst part. Sans probably didn’t _mean_ to whimper softly, hands tangling in the fabric of Papyrus’s sleep shirt as the scalpel started to press against the bloated mass, but his noises shot straight through Papyrus’s soul and rendered it as helpless and wobbly as jello. It was for his own good, but that didn’t really help at all. No painkiller Papyrus had found yet was enough to make this numb for Sans.

Sometimes Papyrus wondered if Sans’s condition would eventually degrade to the point that his magical deposits started hardening, until they would have to carve them away with force. Could Sans’s bones really handle that?

But for now, the excess magic was soft, easily punctured. It only took a moment and a bit more pressure. Like the world’s worst balloon, the mass popped and showered them both in a spray of red, as Sans gasped, spine arching. Papyrus stroked the top of his skull with his free hand, whispering praises of how well he had done until his breathing started to even out.

That took care of most of the mass, and he carefully lifted shreds and bits of it out of Sans’s eye socket and into the little medical waste container. (Which was unnecessary, since it was just magic and would eventually fade away, but if Sans had the equipment, they might as well use it.)

They were lucky this time. Sometimes chunks of it would stick and have to be carefully cut away, where even a twitch could be dangerous and Papyrus would channel his strongest loving intent to make sure Sans’s one HP did not move in the slightest. There was a little shred of it clinging to the rim that he had to dislodge, but everything else was easily removed.

“Let’s see if there’s any more,” he said briskly, reaching for the flashlight next. It wouldn’t do to remove the biggest magical growth and accidentally leave a smaller one behind. There didn’t appear to be, but he examined the socket from multiple angles, and the left as well, in case something had started to form that Sans hadn’t noticed yet, too distracted by the pain in the right. They looked alright, but he’d check again once it was clean.

The worst of it was over. He reached over to dampen a washcloth. Making sure to move gently, as the inside of his socket would be sensitive for the next day or so, he started to wipe away the remaining red liquid. “Is the water warm enough, Sans?” Luckily Sans had wide enough eye sockets that he could reach inside and make sure he got all of it.

“Mm hmm.” Sans was probably still in some pain, but he looked improved already. His shoulders weren’t as stiff, and he wasn’t strangling Papyrus’s shirt anymore, though he was still holding on. Papyrus wrung out the washcloth and did another once-over in Sans’s eye sockets. Who knew what would happen if he accidentally left behind some magical goop? Sans could get an infection and have another tumor formed by tomorrow! Sans sighed and didn’t protest, enjoying the warmth.

Once the interior of Sans’s eye socket was carefully cleaned and dried (he’d get a chill if he walked around with it still wet, after all), he wiped away the drips of red on his face, and the few that had somehow made it all the way down to his collarbone. Even in sickness Sans was unbearably messy, though Papyrus didn’t mind quite so much right now.

“Is it over?” Sans said, his voice slurring faintly. “We done?”

“Yes, brother,” Papyrus said, gathering him up into his arms. “Excellent job.” As Sans buried his skull in his shoulder, Papyrus petted his ribs, first above his shirt and then delving underneath. Making sure to move gently, he reached up to Sans’s soul, which was quivering in place.

_I love you,_ he tried to convey through his touch, hoping his intent was clear. Sending messages was easier when it was two souls pressed together, so he wasn’t sure how much Sans could pick up. _It’s alright now. You’re safe, I took care of it. I love you. I love you._

And, though muffled, as if he was hearing it through deep water, Sans replied. _Love you too, Boss._ Papyrus could feel his Soul calm, settling in Papyrus’s hand as if it belonged there, as if there was no place it would rather be. He could feel the flow of Sans’s natural magic starting to reassert itself and, when he did a Check, his stats had returned to their normal amounts.

Only after he had touched Sans’s soul and confirmed that it was alright could he feel confident that the ordeal was fully over, and he slowly withdrew. Sans sat up straighter, rubbing at his eye socket until Papyrus gave him a scolding look.

Though, now that Sans was cleaned up and sorted, their clothes definitely needed attention. Obviously he wouldn’t let laundry come before tending his brother, but their pajamas looked horrible, and he needed to get them in the wash before the stains set. The towels were old and set aside for this specific purpose, but these were satin pajamas! He wouldn’t tolerate them being ruined!

He quickly darted into his room to change into his uniform, before returning. Sans had gone all pliant and floppy, so it was easy to undress him. “Do you think you can get to work today?” There was no point at fussing and yelling about it; he wasn’t about to send his brother to sentry duty if he was too unfocused to protect himself. It didn’t count as laziness if Sans was putting effort into recovery instead.

Sans thought about it as Papyrus found something clean for him to wear. “...Maybe one shift. I’ll see how I feel after that.” He was starting to become more mobile, raising his arms so Papyrus could slide a shirt over his head, and doing a weird squirm on his mattress so he could get his shorts on himself without having to stand.

“If you feel unwell at all, you will call Undyne and tell her you’re taking the rest of the day off. And you’ll text me if you do!”

“’Course, Boss. Glad we see _eye to eye_ on this.” He had just picked up San’s jacket from the corner, about to hand it back over to him. He threw it instead. (Of course he made sure to aim it at Sans’s torso. His skull was too fragile at the moment.)

“What, Boss, did I hit an _optic nerve_?”

“Are you seriously making a pun right now?! We don’t even _have_ optic nerves, whatever those are.” It was a good sign that Sans was feeling okay, but couldn’t he have shown it in a less aggravating way?

He had the feeling Sans would have winked, had his eyelights been working. It would take some time before they could properly appear, though the blank socket look would hopefully scare off potential threats. “What, do you think these puns are too _cornea_?”

“I don’t know what that’s supposed to mean, but from your tone it must be more terrible wordplay! If you’re well enough to be tormenting me, than obviously you can get ready on your own.” Of course, he lingered a bit after gathering all the towels, in case Sans _did_ need help and called him back over, but he seemed fine, slipping on his jacket and retrieving his sneakers with barely more than a wobble to his step.

He bundled everything into the wash; he had work soon, but he could drop back in to move everything into the dryer so it didn’t get mildewed. He tracked Sans’s steps around the house as he carefully added stain remover, paying extra attention to the creak of the stairs. In case Sans fell, of course; dizziness was occasionally one of his symptoms.

But Sans was fine, when Papyrus joined him in the kitchen. _Better_ than fine, actually: he was now fully dressed and making coffee for them both. Sometimes he couldn’t get out of bed after one of his illnesses. He still looked disoriented and tired, but not terribly so. Maybe Papyrus didn’t have to worry about sending him to work? Of course, he still would, but perhaps a little less.

Papyrus shooed him to his seat at the kitchen table and tied on his apron. Usually they didn’t bother with much breakfast before heading out into the world, but some culinary healing magic would definitely nudge Sans farther along the path to recovery. He bent down to retrieve their battered waffle iron (Sans whistling appreciatively at his rear), which had been shoved back in a bottom cabinet, neglected except for occasions like this.

He made sure to stack Sans’s plate high with waffles, and he didn’t protest when he smeared them in mustard instead of syrup. He even managed to finish most of them before he got to his feet, patting down his pockets to make sure he had his phone and keys. “Think I’ll be heading out, Boss. Damn good waffles, though.”

He took a few steps before Papyrus called out, a thought occurring to him. “Sans, wait a second.”

“Yeah, boss?” He turned back towards Papyrus, skull tilted. “What is it? My fly down? Something stuck in my teeth?”

Papyrus leaned in. “One more thing before you go.” Sans’s eye socket was swollen and discolored, enough that someone might see it as a potential sign of weakness. It wasn’t an acceptable state to be walking around outside! Luckily he had an easy solution.

Of course, as far as eye socket touching went, this was far milder than what they had been doing an hour ago. Sans stood still, not complaining as Papyrus retrieved an eyeliner pen from his inventory and began to outline his sockets in a bright shade of red. Definitely an improvement, he decided, examining his handwork. It didn’t look as good as his own, obviously, more cute than intimidating, but it covered what it needed to.

“Nice. How do I look, Boss? Prettiest guy in Snowdin?”

“No, of course not. _I_ am the reigning champion of beauty in this middling town! However...” Papyrus leaned down, skull aligned with his brother’s, inches apart. He let Sans bask in the anticipation, but only for a few seconds. He was sick, after all, no need to be undeservedly cruel before he finally pressed their teeth together.

It was chaste by necessity; he sincerely doubted Sans had his magic back in line enough to summon a proper tongue. Creating a few bones was far less energy-intensive than crafting an entire magical body part that could properly move on command and take in sensory info. There would be plenty of time for advanced level kissing once Sans was better. For now, it was enough to feel their fangs sliding against each other, close enough that the soft fur of Sans’s hood brushed against his skull. In a perfect world, he would never have to let go.

Reluctantly, he stepped back, giving Sans his best, most roguish smile, which he had practiced extensively in the mirror for times like these. Those cold hours of sentry work would be less burdensome if Sans had a wonderful memory to sustain him, and there was nothing more wonderful than Papyrus himself. “However, my dear brother... You’ve taken second place by _miles_.”

**Notes for the Chapter:**

> I could claim that the title is just meant to be cutesy and random, but nah. I was watching recipe videos and realized the bits of Sans’s burst tumor would look sort of like mashed up strawberries. Delicious! :D


	2. Strawberry Daiquiri

**Notes for the Chapter:**

> Take note of the adjusted rating, which is mostly for this chapter, since the rest will probably be M-rated. And it’s smut that directly involves Sans’s eye condition, so it may be a little squicky. If that’s not your thing, feel free to go on with the rest of this fic, as chapter 2 is going to be the only one with any sex in it. Regular plot will resume in chapter 3.

In all their considerable lives, Sans had never had a heat before.

Heats were a strange, rare phenomenon in the Underground, a period of high fertility that many monsters could go their whole lives without ever experiencing. Despite its rarity, there were a host of laws about heat that Papyrus had learned in the process of becoming a Guard, chief among them that violence against monsters in heat was a far greater crime than typical assault. Someone in heat could very well produce children and, just barely, lessen their inexorable march towards extinction. As such, Papyrus could recognize a monster in heat, in case he had to protect them from the dangers of the Underground.

A monster had to have a specific mindset for heat to occur: they needed to believe they were _safe,_ both physically and mentally, in the kind of environment where childbearing would be not just possible but ideal. Of course there were plenty of monsters that could and did reproduce without heat, but it was universally accepted that heat-born children were stronger and healthier. A parent could not hope for better.

Papyrus himself had only experienced it once before. For them to finally own a home, their own home after years of street-life and shitty apartments... His body didn’t allow them time to unpack their minimal belongings before he was overwhelmed with mindless warmth, longing for Sans to touch him. It was a wonder his brother had realized what was going on, rather than assuming he was sick. Papyrus gladly offered up his virginity (and received Sans’s in turn) that night, too delirious to care that he was being taken on a bare, unfamiliar mattress. Everything had been a haze of safe contentment and pleasure.

However....he hadn’t conceived, nor had he experienced another heat since then. Logically, he shouldn’t have minded. He had been far too young that first time, and neither of them knew how to raise a child, if brothers could bear a child between themselves at all. It wasn’t as if they needed heat to have sex.

And yet, part of him longed for another chance at heat. The loss of inhibitions. How beautifully wild they had become in the flames of Papyrus’s heat, all shame banished. All of his fears about a painful sexual debut, disproved. Perhaps, someday, a chance at childbearing?

But he never brought up that desire. Things were wonderful the way they were, despite the trials of their day-to-day lives. He wouldn’t make Sans feel guilty for his inability to produce a heat, and their sex life was perfectly exciting without it.

So, of course, he didn’t suspect much when he was walking home through Snowdin and people were acting...oddly. It wasn’t unwelcome, for monsters to watch him—they should have been honored to look on his visage! But some of them were smirking, or whispering to each other as he walked by, enough to be noticeable without appearing blatantly disrespectful.

Perhaps, if it had been an eventful work day, it wouldn’t have seemed out of place. But Papyrus hadn’t saved anyone from falling off a cliff, or dusted a notorious criminal, or unveiled a new and cunning trap. Had Sans done something of note, rather than slacking off? Maybe he had gotten into a fight, and news had traveled faster than Papyrus.

Was Sans alright? Usually if he got into a scuff, he kept Papyrus informed, but he hadn’t received any texts. Was it a situation severe enough that he hadn’t gotten a chance to contact Papyrus? Anxiety starting to well up in his bones, Papyrus walked a little faster. Though it pained him to even cross the threshold, he poked his head into Grillby’s just long enough to confirm Sans wasn’t there, drinking away his nerves from a battle.

The tight, suffocating feeling in his ribs eased once he got home to see Sans’s shoes scattered on the threshold, but something was still off. Sans was fine enough to make a mess, that much was obvious: lights left on, a dirty plate on the counter. But he wasn’t at his typical position in front of the TV, becoming one with the couch cushions. Perhaps he was napping?

There was a strange energy in the house, a subtle thrumming under his feet that pushed him up the stairs, accompanied by a scent that grew stronger with every step, warm and faintly spicy. There was something familiar about it.

His bedroom door was cracked just an inch, and the sight drew him closer. Logically he should have checked Sans’s room first, but he remembered closing it that morning. He nudged it open silently.

Sans was sprawled out on his side on Papyrus’s bedspread, bones clattering as he touched himself with a shocking urgency. He was bare except for his shorts, the rest of his clothing puddled on the carpet beside the bed. Almost literally puddled, as he was sweating profusely, and they looked rather soggy. And that scent...

He didn’t notice Papyrus entering the room, his back turned to the door as he chased his pleasure. One hand was fiercely tugging at his lower spine while the other had pressed into his shorts, working at whatever Sans may have conjured down there. He was setting a much faster pace than usual. Typically, if he was going to wait in Papyrus’s room for a surprise boondoggling, he wouldn’t waste his energy long before Papyrus ever arrived. This was far more than a lazy fingering or handjob in preparation for coupling.

And then Papyrus saw the tray waiting on his desk, and everything seemed to freeze. A tray spread out with everything Sans needed when he was sick, sharpened scalpels glinting in the light. Maybe he made some sort of noise or stepped too heavily, because Sans was rolling over to look at him, his socket bright with growing tumors.

Panting, he reached out with both hands, first having to extract the one from his shorts. It came free with an audible squelch, slick with red fluids all the way up to his radius and ulna. “Boss,” Sans breathed, as if this was the start of a normal tryst and not something horrifying. “You’re finally home. Felt like you were never gonna get back.”

He crawled forward as Papyrus rushed to sit beside him, tilting his skull up to get a clearer view. Had something gone wrong, or more wrong than usual? Was his illness making him delirious in some way? The growths hadn’t progressed that far yet; he could see several medium-sized ones inside his socket, but none of them had expanded past the rim. What was different about it that was causing this reaction?

Sans moaned at the chaste touch, and with a jolt Papyrus realized his brother was squirming into his lap, attempting to rub against his leg. His shorts were soaked with sweat and come and, even through Papyrus’s leather pants, he could feel that his brother’s bones were far warmer than usual, as if he had just gotten out of a hot shower. “I missed you so much, Boss,” he was whispering against Papyrus’s chestplate. “And now you’re home...”

“Sans, please, your socket—” He tried to hold Sans still, but he seemed determined to get as much bone to bone contact and friction as he could.

Papyrus couldn’t delude himself about the situation any longer, no matter how much he wanted to disbelieve his training. Sans was in heat. His cheerfully paranoid brother had tumbled into heat, but _how_? Papyrus had just accepted that it would never happen, that it was just a fantasy in the back of his mind. How could Sans possibly be sexually receptive when there were bulging clusters of magic emerging from his sockets? Wasn’t he in pain?

Maybe Papyrus’s panicked confusion was becoming apparent in his expression. Some hint of lucidity seemed to come over Sans, and he pulled back. “Oh, fuck, Pap. It’s okay, I’m sorry.” He started to squirm off the bed, though his limbs weren’t quite under his control; his legs were shaking and he couldn’t keep his hand away, starting to rub at the front of his shorts again. “I can take care of it myself—”

He tried to lurch to the door, stumbling and falling onto the carpet. Papyrus was struck with all the ways a monster in heat could ‘take care of it themself.’ Was Sans going to lurch out of the house to throw himself at any monster who looked his way? Would it be Grillby? One of the dogs? The first Snowdin resident he came across?

Was he so deluded with heat that their relationship didn’t matter to him?

No. Even if Sans managed to find a monster who wouldn’t take advantage or use his condition against him, no one in their wretched little town would treat him the way he deserved. Someone could very well dust him in the throes of passion. None of them would know his limits and sweet spots. Even if Sans didn’t want him, he still needed to protect his brother.

As Sans tried to get to his feet, streaks of red oozing down his legs, Papyrus moved into action, plucking him up and carrying him back to the bed. He yelped, the sound fading into a moan as Papyrus rubbed at his spine, beaded with sweat.

“You will do no such thing,” Papyrus scolded, settling Sans into his lap. “It’s my duty as your brother and lover to tend to your needs and _not_ to let you throw yourself at whatever pitiful monster looks your way. As if they could ever match my lovemaking skills!” And if he held onto Sans, at least he knew that he would be pulled along with any errant shortcuts his brother tried to make.

Sans looked from Papyrus’s face to his pelvis a few times in foggy confusion. “Uh, what about pitiful monsters?”

“I’m not going to let you stumble into the arms of someone who could hurt you, when I’m clearly here for you. Who in this town could possibly satisfy you the way I can? And...” He had to struggle to force the rest out. “Even if you don’t want me, I can still look after you during your heat.”

The words finally sunk in and Sans gave a breathy laugh. “Paps, what? I meant I was gonna go jerk off, not bang Grillby or whoever the fuck. I thought you were freaked out, ‘cause... ‘Cause you were worried about me getting knocked up.”

Oh. In retrospect, that probably should have occurred to him. Childbearing was the _point_ of heat, no wonder Sans had it on the mind. Sans seemed to like children well enough, though there weren’t that many around, and fewer still whose parents would allow them to cross paths with one of the skeleton brothers. Did he harbor some secret longing for a babybones that he hadn’t revealed to Papyrus?

Neither of them needed to worry. Without mutual desire for a child, Sans would not properly conceive, and Papyrus could not suppress his fears about Sans’s health enough to have that desire. Who knew what a growing soul might do to his condition, or vice versa? If either of them wanted a child, _Papyrus_ would have to carry it.

It was childish to entertain such thoughts, absurd frivolous daydreams. Would the Barrier ever break, or was it just a fading wish? Would Papyrus ever be able to retire as a Guard, to live a safe life more suited towards heats? Would he ever have the chance to bear Sans’s child underneath the sky?

None of those hypotheticals mattered when he had his real brother to help. He reached forward, loosely wrapping his arms around his brother. “That’s not what I meant. I thought...that you were rejecting me, though of course that is nonsensical!”

“Could never reject you, Paps. God, could you imagine? I wouldn’t be in heat at all if it wasn’t for you.”

“What do you mean?” Sans pressed his skull against Papyrus’s armor; from hours of being out in the cold, it must have been pleasant against his scalding bones.

“Started getting this mess a few hours ago, right in the middle of my shift. And... It’s fucking weird, but I started thinking about you taking care of it, and bam. Heat, just like that. Like I’ve got a kink for you being my nurse or something. Had to walk back because my magic isn’t working, but I didn’t want any of those monsters I passed, just you.”

“But aren’t you in pain?” Usually by the time his condition had progressed this far, he would cry, or start getting headaches, or struggle to speak properly. This was miraculous in comparison, better than using any painkiller.

“I should be, right? But it’s like my body just....overrode that so that I’d pay attention to my heat. Which would be great if that could happen all the time.” He punctuated that with a jab at his sternum, as if scolding his own body. “It’d be fucking _peachy_ if I could get horny and distracted every time instead of barely being able to function. So...we’d better take advantage of that, Papyrus. Don’t make me spell this out for you.”

It was an odd way to go about things, but maybe with a solid fuck Sans would be more receptive to dealing with his socket. It wouldn’t be healthy to let it sit until his heat was concluded, but he was far too wiggly and distracted to do it safely now. Hopefully he would settle down after an orgasm or two, long enough for Papyrus to remove his tumors. He nodded.

Permission granted, Sans’s hands fumbled at his belt, pulling it free in record time and unzipping his pants. Despite his misgivings, his length was already summoned and hard. The scent wafting off of Sans was too much to resist, and the way he was grinding against the bed and leaning his head down closer destroyed the remainder of his self-control. Papyrus was well-acquainted with his brother’s oral skill and yet... He was aiming Papyrus’s cock not at his mouth, but higher up...

“Sans! Wait, what are you doing?” He took his brother’s skull in his hands, keeping him from going any farther.

“Trying to fuck you, what’s it look like?” Sans panted. “Please, Boss, you’re killing me here. Now’s not the time to make me beg for it.”

“In your eye socket?! Are you insane?”

Sans clutched at his arm, giving him a pleading look. Having bulging growths coming out of his socket did have the remarkable effect of making him look smaller and more pitiful, not so different than those watery expressions the dogs bore when he scolded them too harshly. “It doesn’t hurt at all, I swear, but it _itches._ Boss, please, I just...I want you so badly.”

When Papyrus didn’t respond, he slid a few fingers into his mouth, sucking briefly before he raised them up to his socket. Papyrus winced, expecting the worst, but as Sans started to probe into his skull, it looked...fine? Better than fine, if Papyrus’s erection had anything to say about it. “See, bro. It’s not that big a deal, look.” He managed to press in all the way to his metacarpals without a flinch, moving them in gentle circles, his thumb stroking at the rim.

“Sans,” Papyrus started, with a deep breath to gird himself. “Please be honest with me. Are you absolutely sure?”

Sans pulled his fingers out, giving them a slow, thorough lick. From his grin, he knew exactly what that was doing to Papyrus’s pelvis. “Can’t be more sure than I am right now. Get your dick in here before I explode.”

When he shooed Sans off the bed, he obeyed easily, though he didn’t want to break contact with him for even a second, a hand on his femur. Papyrus tossed down a couple of pillows for Sans to kneel on and a towel to put over them, to keep the carpet from potential come stains. (It wasn’t as if he could make Sans wait for him while he scrubbed it out, of course.)

With Papyrus sitting on the bed and Sans on the floor, he was at eye level with his dick, which was still straining and hard, trickling red precome. Eagerly, Sans reached out and gripped his erection, stroking a few times to spread it down the rest of his shaft. Apparently he was too excited to draw it out for very long before he dipped his skull down closer and guided it to his socket.

  
He hadn’t expected the texture of Sans’s growth-filled socket to be so plush and soft, as he hesitantly inched his tip inside. It was cold but not unpleasantly so, especially with the heat that was radiating off the rest of Sans. The sensation was something like a luxurious cock sleeve that had been chilled in a freezer for a few hours.

In their varied erotic adventures, extensive as they had become, they had never explored eye sockets as a form of pleasure. How well could that part of their body register sensations other than pain? He tried to think back, but all he could think of was the agony of his socket being gashed, how long it had taken to heal.

He made sure to move slowly, barely a few inches of his length inside of San’s skull, not pressing too hard on the growths inside. Fighting down the urge to thrust deeply, he rocked those few inches in and out, ready to stop the moment Sans looked uncomfortable.

It wasn’t a particularly intense act, but from the noises he was making, Sans certainly seemed to enjoy it. Were his eye sockets more sensitive during his sickness, or was it just the heat? It was as concerning as it was appealing; just because he couldn’t feel pain normally didn’t mean he couldn’t take damage. Papyrus didn’t want to ruin Sans’s first (and possibly only) heat by wounding him.

Despite the slow pace, it was becoming pleasurable for him as well. Cautiously, he started to move a little faster, though the pace was still sedate. Sans pulled down his shorts with his free hand and began to finger himself again. The room filled with gentle moans and slick noises.

However, Papyrus had to keep his lust from distracting him. Coming in Sans’s eye sockets would probably be a terrible idea; he didn’t need excess foreign magic on top of his own. Of course, he had impeccable control of his own orgasms, but the way his brother looked was weakening his resolve. There was a faint line of drool running out of Sans’s parted teeth, and his femurs were practically soaked in translucent red. It was hard to contain himself at the sight. His next thrust was too vigorous, his pelvis clacking against Sans’s skull.

_And something gave._

A rush of red liquid splashed down Sans’s face, Papyrus’s length burying itself a few inches deeper, nearly hitting the back of his socket. The liquid wasn’t ejaculate; Papyrus was getting closer, but his orgasm was still on the horizon, retreating at his slow realization that the liquid was coming out of Sans. He tried to pull back, but Sans had stopped fingering himself to clutch at his hips with unexpected strength. He moaned deeply as more and more crimson seeped out around the dick still inside his skull.

“Sans, are you alright?! Brother, please use your mouth for something other than lewd noises. Are you dying??” Papyrus attempted a Check, but Sans’s HP was unchanged, and the rest of his stats told him nothing. (Though he did notice that his brother’s DEF was the highest he’d ever seen, which soothed his panic by a hair.) If he was in any danger, it didn’t show from his expression: his remaining eye light had turned into a fuzzy heart, his tongue gaping from his slack jaw. Sans rocked his skull so Papyrus moved farther in, hands clutching so tightly that Papyrus could feel the pinpricks of his claws through his pants, still bunched up around his legs.

“I think you popped one of them,” Sans said in a faint, dreamy voice. “It feels so good, bro... Please keep going...”

“Sans! Did that hurt you? I can’t—” Again, he tried to pull out, but Sans only let him retreat an inch, his shaft emerging with a sheen of red and a few shreds of solid magic clinging to it. It was strangely erotic; although it was darker and colder than the emissions Sans produced from his genitalia, it served the same purpose. His movements in Sans’s eye socket were much smoother, and he had to suppress his own groaning as Sans drew him back in.

“C’mon, Boss.... Is this that different than popping them with a scalpel? I think I like this way a lot better. I mean, right now I could probably still get it up if you jabbed a knife in there, but this fits the mood, right?” With Papyrus motionless, Sans started to fuck himself on Papyrus’s cock, his skull bobbing at a faster pace than the one Papyrus had set. With another, fainter pop, another trickle of red leaked out. Sans licked at it as it oozed down his face.

Their safe word rose to the top of his mind. If he said it, he knew Sans would stop immediately, heat or no, but... If Sans was safe, did he really need to stop? Sans didn’t seem to be in pain or even discomfort. There weren’t little gray specks of dust mingled in with the release. “Are you certain?”

“Hell yeah. Fuck me ‘til they’re all gone!”

His first few thrusts were still cautious, unsure of whether he could really proceed, but Sans soon put a stop to that. “C’mon, can’t the _Great and Terrible_ _Papyrus_ give me a good pounding? This is pathetic.” His tone was teasing rather than serious, but it was enough to spur him on. Papyrus soon picked up a vigorous rhythm, feeling tiny growths popping under the head of his cock. Sans even tilted his skull at different angles, so Papyrus’s cock could ram into the tumors on the sides. The larger ones took a few more thrusts before they burst, sending more and more red streaming down his skull, painting it beautifully.

How had they never tried this before?

He would have to examine Sans’s socket later to make sure he hadn’t missed any growths, but it felt like he had cleared them all out, his cock rubbing against nothing but smooth bone. The resulting mess of liquid and shredded magic was still stimulating enough for him to continue, but he was reaching his limit.

“Sans.” He tapped at his brother’s cheekbone, to make sure he had his attention. Perhaps it was unnecessary, with that adoring look Sans was giving him, but he wanted to be sure. “I’m going to pull out and move to your mouth, understand? I’m not leaving, just changing position.” It took an enormous amount of self control to draw away, but the promise of his brother’s mouth was just as enticing.

“ _However_.” He held Sans’s jaw shut, his dick running across the face of his closed teeth and leaving a trail of residue from his socket. “When I finish, you will not swallow my seed, as wonderful and delicious as it may be. If you manage to hold onto it, you’ll get a reward.”

From the way Sans’s eyelight brightened, Papyrus probably didn’t have to worry about him swallowing. Maybe it wouldn’t harm Sans’s condition to ingest any magic, but now wasn’t a good time to test that. (Would they ever have a chance to try this again without heat? Would it still be pleasurable?) It was possible that _any_ semen might count as excess magic, and Papyrus would need to entertain Sans with his cunt.

(And his fingers, and toys. Who knew if his genitalia could hold up for the duration of this heat?)

He started to thrust into Sans’s mouth, and Sans took him in eagerly, his tongue winding around his cock. The warmth of his mouth was deeply welcome after the chill of his eye socket. It was tempting to go farther, to press down into Sans’s throat, but he didn’t want to risk the chance of coming while he was buried that far in.

It didn’t take much more stimulation. With a groan, he filled Sans’s mouth with crimson, withdrawing so he could close his teeth before any of it could escape. Without giving Sans time to react, he moved off the bed to sit beside Sans and trailed his hand down the channel of his vulva. He was so wet he was practically flooded, and Papyrus slicked up his gloved fingers. Only a few rough circles around his clit and Sans had already tipped over the edge, his bones clattering. If his mouth had been free, Papyrus was sure he would have wailed.

To his credit, barely a trickle of come had leaked out between his teeth when he finally sagged against Papyrus. “Did you swallow any?” Sans shook his head. “Good boy.” Papyrus reached over for the abandoned towel, holding it up to Sans’s face. Logically, there was no need to be squeamish, considering how much bodily fluid was yet to come, but he still looked away as Sans opened his mouth to let the mess of come dribble onto the towel. Carefully, with a cleaner corner of it, Papyrus reached into his brother’s mouth to wipe the rest away. Ideally he would have gotten him to rinse out his mouth too, but Sans probably was too heat-addled to be convinced.

For once, Sans’s stamina exceeded his own. With barely a pause, he was on top of Papyrus, pressing him into the carpet and kissing him fervently. It would take far more than that before his heat ended, though Papyrus wasn’t sure how long it would last. How had Sans managed to keep up with Papyrus’s heat? He could be like this for _days,_ and Papyrus would have to pace himself. Hopefully they had enough food in the house to last, because he couldn’t imagine leaving Sans alone to go get groceries. And they might need time off...

But that minutiae would have to wait. The warmth exuding from Sans’s bones was seeping into him, filling him with lust, the urge to keep mating. It would probably take mere minutes before he would be able to change his genitalia, ready for a second round, but until then...

He quickly flipped them over, and Sans didn’t struggle as he was pinned down. Calling out in ecstasy, he arched up, pressing his skull closer as Papyrus let his long, serpentine tongue loll out of his mouth and into his brother’s eye socket. He had braced himself for it to taste unpleasant, but it was rather sweet, with the faintest taste of cherries—not as appetizing as his brother’s come, but hardly terrible. There was no sense in letting that mess dry, especially now that he had time to clean it up. The solid pieces were a little more unpleasant against his tongue, so he carefully fished them out with a fingertip, smirking at Sans’s moans.

If he could get his brother to come again just from this, all the better.

**Notes for the Chapter:**

> It’s more fun and porn-appropriate to imagine that skeleton monster eye sockets are actually much deeper than human sockets.


	3. Empty Glass

**Summary for the Chapter:**

> The human faces a skeleton in the Judgment Hall, but something is wrong.

**Notes for the Chapter:**

> Note the new archive warnings and tags for this chapter. The violence is mostly contained to 3.

Sans the Skeleton wasn’t having a very good day.

They peeked around the doorway into the golden hall, trying to get a decent view of what was happening inside. It didn’t look quite as golden anymore, with almost all of the stained glass windows shattered on the floor. Some of the columns were torn up, everything covered in bits of stone and non-person dust. They weren’t sure how long he’d been at it, destroying the Judgment Hall, but it didn’t look great. Maybe it had been hours, ever since they had finished up in Snowdin. How long did it take Sans to realize that his brother was dead, before he must have immediately come here?

He should have saved his energy. Clutching their new knife, Frisk stepped out into the hall, ready for another fight, another win. Would he be a boring one-hit-kill, or would it be a struggle, like with Undyne? Sans was turned away, so maybe they could get a solid swipe to the back...

Their shoe scuffed against the floor, knocking away a bit of rubble, and Sans turned around. A cage of bones stabbing up through the floor around them at his gesture. In the moment that they could see him, before another bone hurtled through the ‘bars’ and straight into their eye (maybe passing out the other side, but they weren’t in a good place to know, by then), they could see that Sans the Skeleton looked about as awful as he must have felt.

Awful in a good way, though. A pretty kind of awful, like a weird fantasy painting in a book. There were ruby-colored crystals jutting out of both of his eye sockets, a few inches long and super sharp looking. Smaller crystals had emerged from the crack in his head, which looked wider now. Some of his teeth had been pushed out of his skull, including his golden tooth, and they were replaced with more crystals, jamming awkwardly against his remaining fangs. His t-shirt was torn, and they could see a faint red glow past it, and it looked like there were more crystals jabbing up from underneath the shirt. His ribs were probably turning into it as well.

(There were red smears under his crowded sockets, and on the right socket it nearly looped down onto his cheekbone. So it really was makeup that the skeleton brothers wore, not just the monster version of eyebags. They guessed he had tried to put on eyeliner after he had been blinded, and that was why it was such a mess. He would have looked clownish except for the rest of his everything.)

Apparently he wasn’t as much of a skeleton as he was a crystal monster now, they decided as they reloaded outside the room, patting at their face to confirm that they didn’t have a bone still sticking through it. _Red_ crystal, too. Maybe Sans was really determined for a monster, though that didn’t mean much; at most, probably a few drops as compared to their gallons of it. It wasn’t going to stop them from getting past him.

Now that he was blinded, though, they had to be more careful on a floor that he had basically booby-trapped with a thousand bits of crunchy glass and rock. And every time he heard them, it was bones on bones on bones, before they had any chance to do anything, let alone attack. The second time, he sent a bone through their stomach, and they had enough time to look down at it, to see that the whole bone was streaked with veins of crystal. It probably didn’t change anything about the attack, but it was very pretty. The ones that punched through their ribs and into their heart probably were too.

Sans was falling apart, but he still managed to kill them, over and over. They couldn’t even reach the battle menu! But from the way he looked, it was possible that the crystal was still spreading through him, and maybe if they waited, he’d change so much that he wouldn’t be able to move or use magic. _Or_ it was making him stronger, and if they waited, he’d get so overpowered that they wouldn’t have a chance. And if that was the case, they were in trouble. Resetting all the way back just so they could try to get to him as quick as possible, well... It sounded like a huge waste of time, not when they were so close to sunlight again.

(They wanted it to be over.)

His hearing apparently wasn’t sharp enough to catch their breathing, so they hung by the doorway to look at him. It could’ve just been a tantrum, but the more they looked at the room, the more it seemed totally deliberate. The ground wasn’t just noisy—all that debris could trip them and tear up their hands and knees if they fell trying to make a run for it. There was barely any clear space to step on. Even if they did make their way through stealthily, all that dust in the air was ready to make them cough and sputter their way to giving up their position.

If they did manage to sneak past him, they wouldn’t have to fight, but... It was doubtful that Sans wouldn’t be able to hear them fighting Asgore. A two-on-one battle with such powerful monsters would be impossible. One way or another, Sans had to go. How much EXP would he give them?

They tried a few more times, all of them failures. A glass shard through the sole of their shoe, and though they had had much more painful wounds, their little squeak cued Sans in and he attacked instantly, blasting them with a laser out of an enormous floating skull. Trying to rush him, which only got them bone spikes through the knees. Brushing a clear path through the mess, which he heard instantly and put a stop to.

The whole time he was silent, every time he killed them, no battle speech like Undyne or Mettaton. With all that crystal growing in his head, _could_ he talk at all? They weren’t sure how skeletons talked without all the fleshy throat bits other people had, but maybe Sans’s talking parts had been wrecked by this crystal. If he had a long-winded speech about how they had taken away his only family, they could have had an opening.

They tried to throw the knife at him, just inside the doorway, and it made it about a foot through the air before dropping to the floor with a clatter. Sans didn’t look up as he jerked his hand up, bone spikes skewering up from under them and ending everything, _again_.

It wasn’t a challenge, not like with Undyne. Her attacks had been brutal, but this was _impossible_. What monster could have that many bullets summoned all at once? This was a puzzle more than it was a fight, and Frisk was going to solve it one way or another.

So they tried waiting him out. As long as they didn’t save again in the process, it’d be fine, even if it waiting ended up making him stronger. For nearly an hour, they peered around the doorway, trying to hold their breath as much as possible. He didn’t do anything all that interesting, just pacing around the middle of the room. Had Asgore overheard any of that destruction? Had Sans killed Asgore himself? The thought burned in their stomach, and they had to grip onto the doorway to keep from rushing him and ruining a good hour of waiting.

There was no way to tell if any of the mess on the floor was actually monster remains. If Sans had been so trigger-happy that he had torn Asgore apart when he came to check what all the noise was... They’d be trapped in the Underground without a monster Soul to carry them through the barrier, trapped in a pit with nothing but a bunch of dead bodies and an inevitable reset. All of that struggle and effort would be completely wasted just because of fucking Sans the Skeleton. At that point, even if they did have to reset, they’d have to kill him anyway, just for revenge.

They were more determined, though. The floor hurt to sit on, and they were getting a headache, but they were going to try out patience, no matter how long it took to see what would happen.

Eventually, his pacing trailed off. Vengeance or no, that was a long time for a guy like him to stay on his feet. He should have conserved his energy, obviously! So for a while after that, he just stood in the middle of the hall, wobbling unsteadily every now and then. Was the plan actually working? If they squinted, they could almost see little sparkles of red trailing down from under his shorts. Was it growing down into his legs? His arms were too bundled up to tell if they were getting the same treatment.

From the way Sans was looking around, he obviously expected them to have showed up by now. They had to wonder why he stuck to this room with every run, instead of just going out to look for them. The deaths would have happened even faster if he had been waiting for them at the entrance to Asgore’s house or something.

By now, he wasn’t really in any shape to go searching. With a final wobble, Sans lowered himself to the ground, not seeming to care that he was dropping down onto a pile of glass. From their spot across the room, they could hear his shorts tearing a little. Was it just them, or had the crystal coming out of his left eye grown bigger since they had first arrived? From the way his skull was bowed, it must have been heavy.

Their whole lower half ached from sitting at this door, and they hadn’t let themself eat anything from their overstuffed inventory in case he overheard, and their eyes hurt from the bright light of the Judgment Hall, but it was _working_. The longer they watched, the more exhausted Sans looked and the farther those growths spread across him. He didn’t have eyes to close or a voice to snore with, but his shoulders were getting more slumped, and he couldn’t keep his head up for more than a few seconds at a time.

When the crystal inched around the sides of his head, where other monsters had ears, they wondered if that was it for his hearing. Not that they wanted to test it and potentially waste hours of waiting on a guess, but it seemed likely. It was starting to come out of one of his kneecaps too, a spike that looked ready to separate his lower and upper leg bones. There was a widening tear in his heavy jacket where another bit of crystal was growing from his shoulder.

Even if he hadn’t been waiting for an attack that was several hours overdue, they doubted he could lay back on the ground, his body solidifying into position. By now, he had more red than white on his visible body parts, and probably a lot more underneath his jacket. Aside from painful twitches, he wasn’t moving. They were used to the skeleton brothers breathing, though they obviously didn’t have lungs, so when Sans stopped...

They weren’t going to be careless now. Taking their shoes off, since their socks were a little quieter, they made their way across the room, stepping as carefully as they could, so they didn't get a shard of glass through their foot. They pulled their sweater collar over their mouth just in case, but most of the floating dust had cleared. He didn’t move during that approach, but was that because he couldn’t hear them, or because he couldn’t move by choice?

They stood above him, watching the crystal inch its way out of his mouth, pushing down another tooth. It had been getting faster and faster since he had sat down. If they waited long enough, would the whole thing fall out completely? If he didn’t dust, would he turn into some strange, skeleton-shaped statue destined to sit here forever?

(Maybe he would starve instead, before that happened. Even for them, it was too horrible to imagine him staying conscious in a statue forever.)

In a suddenly clammy hand, they raised up the knife. It had to be almost merciful, to free him from whatever curse this was. What was it about murdering everyone that had turned Sans into a piece of jewelry? Could it really just be grief so strong it was physical? It was a little disappointing that he couldn’t tell them and probably wouldn’t have anyway.

As far gone as he was, Sans must have felt the air move as they drove the knife down across his front. They could feel the attack connecting, a jolt going up the knife and into their arm from where it tore through his shirt to grate against bone and crystal, before everything sharpened into pain. His final attack burst around them, bone spears tearing through their legs. A second too late to stop their attack.

His aim was off. If he had been able to see, he could have sent bones through their neck, their head, somewhere that would have been lethal. Or he could have aimed for their arms before they had a chance to bring down the knife. Not that it wasn’t a good attack, obviously: they could even see their own bones, just a little, if they looked down. It was a great attack, but not enough to stop them. They still had 1 HP left.

Sans opened his mouth slightly, as much as he could, and they could see how much crystal was inside. He managed a faint croaking sound, barely audible, before his whole body collapsed into a cloud of dust, his attacks vanishing with him. Their knees buckled and they fell without those bones to keep them propped up, barely managing to keep from face-planting into his remains.

20 LV and 1 HP, and they didn’t know whether to laugh or to cry, but it was over.

It was _over_ , but there was no way they were going to drag themself back over broken glass and to the save point, not with that much blood coming out. And was that visible muscle? It was hard to resist the urge to stick their fingers inside and wiggle them around. Maybe the pain was making them a little loopy.

Instead, they jammed a brick of uncooked instant noodles into their mouth and tried to look away from the literal holes in their legs, slowly reforming as they tore off the top of the seasoning packet and poured it out on their tongue. Monster food really was miraculous, though it didn’t do much for the pain. It was enough to let them limp across the room, to the save point that they hadn’t gotten a chance to use before. Sans struck them down whenever they tried to get close. They raised their hands into its golden light and sighed in relief.

Now they had an opportunity to look back at the dust pile that had been Sans just a minute ago. Rather than normal gray, Sans’s dust looked like red clay mixed with glitter, scattered on his fallen black jacket. Not the sort of remains that would get lost in the snow, that’s for sure! Not like Papyrus’s.

They never really figured out why some things stayed around when a monster died. Was it part of their funeral traditions? It wouldn’t surprise them if Papyrus’s scarf and Sans’s coat counted as their most precious possessions, so no one needed to go through the trouble of spreading dust when it was already there. Not that anyone was around to do it, but...

If it hadn’t gotten so torn up from those crystals, maybe they would have taken the jacket with them. It was a nice jacket, and the fur on the collar looked so soft, though for some reason touching it felt forbidden. They could have checked his pockets to see if he had anything cool, though they didn’t know what they would do with all the gold they had earned once they were back on the surface. But something about Sans’s jacket seemed forbidden. Contagious.

For five minutes, ten minutes, they sat in the glow of the save spot until the pain faded into tingling. If Asgore hadn’t come out before, then the sound of Sans’s final attack wouldn’t be enough to draw him out. (If Asgore was still alive.) They could have a little break and use the box now too, nibbling at a glamburger mostly for something to do with their shaking hands. If the battle against Asgore really needed that one wasted supply, they could hike back to the hotel. If Burgerpants had finally evacuated, now that his boss was dead, there would probably be food left behind.

Another save and they were good as new, ready for the next fight.

**Notes for the Chapter:**

> A little frustrated with this one, but oh well.


	4. Refilled

Sans’s death was a cruel, horrible thing, and Papyrus made sure to watch all of it.

It wasn’t that he was doing a bad job. Despite his blindness, he was battling with all of the cleverness and power that Papyrus knew he had. But, now that he was dead, Papyrus could see the flow of time skipping bizarrely, could see how many times Sans had to endure it before it finally ended. From the way his attacks evolved with each attempt, maybe he sensed it rewinding? It wasn’t enough to save him.

The blow finally came down, the human child’s knife slashing down his ribs, his bones stabbing up into them in retaliation. If his counterattack had been a second earlier, it could have felled the child, but... This was easier in the long run. He could be proud of the injuries Sans had left on that abomination’s body; they were already reaching to heal themself, but he hoped the memory of that pain would stay with them. It was horrible for Papyrus to want it to be over, for Sans just to die so he would be spared those few extra seconds of pain, but...

All of him seemed to give in at once, his entire body dissolving into crystalline dust and his spirit landing on the golden tile in front of him. Papyrus was finally free to touch him, and he rushed forward, intending to lift his brother up. The human, still bleeding in the corner, meant nothing to him now.

Why wasn’t death fixing him? He was still blinded, those horrid crystals jutting out of him at every angle. Sans turned his head up, turning from side to side in confusion. Surely he could recognize Papyrus just from the feel of his gloves, but he shouldn’t have needed to rely on that alone.

Papyrus hadn’t been dead for long, but he was getting a grasp on how it worked. Death erased the marks of their lives; every time he passed a mirror or a reflective surface, he had lost another scar. He had seen it in Undyne as well. The damaged tissue normally peeking out past the edges of her eyepatch had receded, and soon he expected her whole eye would grow back. And the damage of their deaths had disappeared almost immediately; her emergence as a spirit had shown none of the liquefaction of her death, though he had only seen it from a distance, mourning for her but more dedicated to following his brother.

Sans shouldn’t have been this damaged.

There was still an oozing red slash across his front. Still crystals bursting from his eye sockets, his joints, his mouth. Papyrus could see a hint of them inside of his ribs, from where his shirt and jacket had been sliced through, and his clothing wasn’t reforming its damage either. Could he hear Papyrus’s mumbled reassurances?

He gathered his brother into his chest, stroking at the back of his skull and trying not to flinch at the growths he found there. Surely he couldn’t feel the pain anymore, right? It had to be okay. He just needed time for it to vanish. It seemed like a cruel thing to prolong it now, after he had been through so much, but Sans could get through it, now that Papyrus was with him again.

“Boss?” Sans mumbled, the words broken up by the protrusions he spoke around. “Are you really...”

“I’m here,” Papyrus said, willing his voice not to shake. “Everything’s over now.” Carefully, he picked his brother up, making sure he was properly supported: one arm under his knees, the other around his back, pressing Sans’s skull against his chestplate. He was tired of seeing this hall, the golden light far too bright and cruel, the dust and blood on the floor. They needed to take their leave.

Luckily, the world was easy for the dead to shape around them, and Papyrus could walk out of the Judgment Hall and into Waterfall in a single step. The darkness and the sounds of the water appealed to him right now; Snowdin had too many painful memories.

(Once Sans was settled, they would pass through the Barrier together. It was doubtful that it could bind the dead. Hopefully soon, he and Sans would go there—it was just a pity they couldn’t have seen it while still alive.)

“Wha’s happenin’...” Sans mumbled, rubbing his face against Papyrus’s armor for just a few seconds, before the crystals in his sockets start to scrape.

“We’re going to Waterfall, brother.” Well, technically they were already there, but he didn’t want to overwhelm Sans with the new realities of their afterlife. He sought out a corner of Waterfall beside a stream, no spirits around to bother them or screaming, begging Echo Flowers. Undyne was likely around here somewhere, but searching her out could wait until Sans was in a better condition. He sat in the grass, cradling Sans in his lap.

Perhaps it was better to be honest. He leaned forward, scooping a handful of water up so he could rinse the dust from Sans’s shirt and bared ribs. They were still broken, another thing death should have already erased. The marks from his own beheading had faded in minutes. Did Sans still think he was alive, and that was why? Did their thoughts have that much influence?

“Brother. _Sans_. You....well, both of us are dead. You fought your hardest, and I’m deeply proud of you, but it’s over.” He waited, hoping that statement would be enough to fix the whole thing, but nothing changed.

Sans chuckled, though something scraped inside of him at the sound. “No wonder I feel like shit, Pap. Thought this was a dying dream.”

“Sans...You shouldn’t be feeling any pain. It’s over now.” He brushed a hand over the crystals that had forced Sans’s gold tooth completely out of him. Would time in the afterlife eventually regrow the original tooth? It had been so long that it would be strange to see a brother without skull cracks and a false tooth. “And these should have vanished. We don’t carry injuries with us. I know you can’t see it, but...” He guided Sans’s hand up his cervical vertebrae, letting him touch and stroke. “As you can feel, I’m in possession of my head once more.”

“Sounds too good to be true, Paps. Believe it when I see it, but...” He stopped to cough, and the force of it sent chips of crystal spraying into the grass as he turned his head. “...can’t really see right now.” That brief, rattling cough seemed to drain what little energy he had left, and his body went slack. Even with the absence of a snore, which he didn’t seem capable of now, he was clearly asleep.

Well, he had just _died_ , and after a battle like that, Sans deserved a bit of rest, though Papyrus wanted him awake desperately. Just a few minutes. He reached forward to dip his gloved fingers in the stream again, bringing them up to Sans’s face. At least he could clean off the remains of that horrible makeup attempt. Sans mumbled but didn’t stir, letting Papyrus clear away the smears of red eyeliner and the drips of sweat still lingering on his skull.

If it wasn’t for his illness, it would have been a beautiful, melancholic moment. No responsibilities or worries, nothing that could bring them harm. Just the sound of the stream and the ability to hold his brother.

The nap should have started to erase Sans’s illness, but the crystals didn’t seem to change, no matter how much he stared at them, willing them to shrink or to fall out of Sans’s skull. When Sans finally stirred back into consciousness, he wasn’t improved.

He didn’t want to be too hard on his brother in his first hours of being dead, but this was a quality of (after) life issue! The sooner he had that mess removed from his body, the better off he would be! How was he supposed to show his brother the Surface if he was blinded and could barely walk? Papyrus had yet to venture to the Barrier, wanting Sans either alive and safe or beside him before he explored the Barrier’s impact on the dead. Supposedly some monsters had tried and successfully passed through, but he didn’t want to mindlessly accept gossip as truth. If people _had_ passed through, who had stayed behind to pass that rumor along?

He needed to take more proactive measures.

Sans’s condition had never gotten this bad before, and he wasn’t sure how to proceed, but he had to do _something_. Would any of the methods they had used in the past actually work for something like this? He ran his gaze and hands over Sans’s body, shifting his jacket aside, but none of the growths were as malleable as he was used to. Was he supposed to _carve_ the crystal out of Sans? It wasn’t like he could die now, but that didn’t make it less horrifying. Did he have any feeling left in those growths? Would his bones crack if Papyrus made the wrong movement?

Luckily he didn’t need to trek all the way back to Snowdin and its terrible memories to retrieve his tools. He couldn’t interact with physical objects in the living world, but he could imagine an object and there it would be, ready for him to use. He had successfully conjured up a new scarf to wear within minutes of dying, though he hadn’t experimented with it beyond that. Who knew what the rules of being dead were?

A scalpel wasn’t enough for this; he was sure it would grow dull in seconds against solid crystal rather than a soft mass. What else could he use? Sans didn’t have HP to lose now, but he still instinctively flinched at the thought of taking a...a drill to his own brother’s body. A hammer and chisel? Was there anything more gentle that would actually work?

“Sans.” He immediately stirred at his voice, and that sent a pang through Papyrus. Even in death, the paranoia still stood: fast to sleep but faster to wake at the smallest sign of potential danger. “I still want you to try and imagine all of... _this_ away, and it really should be vanishing by now, but I’m going to try to help it along however I can. I...I’m going to carve this out of you, if necessary. You don’t deserve to have to carry this around with you for another second.”

It would have been reasonable for Sans to demur, to object to having himself borderline mutilated. But he just shuffled up into a sitting position within hugging range, though he could barely lift his arms, and Papyrus completed the rest of the hug. “Sure thing, bro. Get this shit out of me.”

Now that he had permission, he wasn’t sure where to start. What would benefit Sans the most? Probably his skull—the weight of those crystals made his head droop in an alarming way, never mind his blinding. How much strain did that put on his spine? It was amazing he could have stood upright for so long in the Judgment Hall, and Papyrus couldn’t help dipping in for another hug.

“You getting cold feet here, bro?”

“Hush! I’m...merely thinking of a plan of attack!” On the other hand, as much as he wanted Sans to be able to see as soon as possible, starting with his skull was intimidating. A lifetime of facial and eye socket scars could attest to that. Even if any damage Papyrus potentially caused would undo itself, he wanted to start with something less vital.

He helped Sans lay out on the ground, scanning him. There was a jut of crystal on one of his knees, and that seemed like a sturdy enough bone to withstand a hammer blow, right? Removing that would definitely be adequate practice to work on everything else.

After pushing Sans’s tattered shorts up his femurs (he really needed undamaged clothing; was that another thing he would be able to manifest?), he imagined a hammer—not a regular one for home repair, but a rock hammer with both a flat head and a chisel, the kind to open geodes with. He had a few memories of Gerson demonstrating it to a crowd of monster children, and for once, Papyrus hadn’t needed to worry about being attacked or pickpocketed, trusting that the old turtle would keep order.

He shook his head, dispelling thoughts about whether Gerson had survived or not. How much pressure did he need to use? It seemed like extremely hard rock, but maybe...

“You’re gonna have to put more oomph into it,” Sans slurred out. “Barely felt that.”

“It was just a test hit!!” For a moment, he considered holding Sans’s leg steady, before realizing how incredibly stupid it would be to have his comparatively fragile hand in the way of a hammer strike. Instead, he wreathed Sans’s leg in blue magic, so that he wouldn’t accidentally flinch out of the way of the blow and catch it on bone instead. Aiming for a corner of the growth, he began, soon finding the right level of force after a few useless blows.

His movements became less timid as bits cracked off, forming new corners to aim at. His patella wasn’t cracking open under the strain. Could Sans still feel pain in it, when it had progressed this far? He certainly didn’t sound like he was in agony, though occasionally he sighed in discomfort.

Sooner than he expected, Sans’s legs were as clear as he could manage, and he brushed away ruby chips off into the grass, where they began to evaporate. “How are you feeling? I’d like to start working on your spine next, but...” But what if that was too fragile? What if he made a mistake?

“No complaints here,” Sans said. He bent his leg up, and although a red dust drifted out as his bones slid together, the movement was smooth. “Go for it.”

Out of everything, his t-shirt was the most damaged, practically shredded by the crystals cutting through it. Luckily Sans didn’t have any emotional attachment to it, like he had with his jacket, and once Papyrus had eased the latter free and set it safely aside, he summoned a sharp bone to cut the rest of the shirt away. They could find another later or imagine one into existence.

Without those shreds of red fabric concealing it, his rib cage and spine looked dire. Barely any of his vertebrae were visible, wrapped in a column of crystal that had also enveloped most of his ribs, spikes jutting from it at random. Where was he supposed to begin? How was he supposed to reach the insides of Sans’s ribs? He scanned the whole of his torso and shifted around to peer in through the bottom. There had to be a weak point somewhere... His gaze caught on a lump in Sans’s rib cage—not an offshoot growing from one of his ribs, but a free-floating object...

“Sans—your soul—” It was rare for him be this speechless. How had Sans managed to last after Papyrus’s death if his very core looked that brutalized?

“Fucked up, right?” Sans let out a chuckle that made the crystals inside him grind together horribly. “Started going hours after you died. My soul just couldn’t take it anymore, I guess. Not much point to fixing it; trying to operate on my own soul would’ve wiped me out with one wrong move.”

He tried to gather himself. Being confident would only steady his hands, and hopefully it would ease any nervousness Sans might have been feeling, though he looked as calm as someone could be when their body looked like a geologic formation. As much as he wanted to start with Sans’s soul, he couldn’t reach it with the rest of the crystal in the way. With everything that crusted over, he didn’t want to try to move it out of his rib cage yet; there were too many spikes and protrusions in the way. He had to work his way in.

Slowly, Sans’s ribs began to emerge from the mass, and they were beginning to heal too. If they had been alive, his bones surely would have chipped, no matter how careful Papyrus was. But now, they didn’t have HP to lose. By the time he moved down to the floating ribs, he was becoming more and more certain that they _couldn’t_ be injured anymore. He still considered each blow before making it, but he was picking up speed. He could free Sans’s soul soon.

Luckily it hadn’t fused to the crystal around it, so with a careful touch of blue magic, Papyrus began to draw it out. It was far heavier than it should have been, but it wasn’t a strain on his expert magic. It looked worse up close, and he had to wonder how painful and uncomfortable it must have been while he was still alive.

How was he supposed to fix this? Taking a hammer to his brother’s soul was unthinkable, post-death invulnerability or not. Feeling foolish about resorting to fairy tale methods, he lifted the soul up to his mouth, its surface fogging with his breath before he brought himself to kiss it gently. A few flakes of crystal fell free and onto his hands, but that was clearly not enough. As much as he would normally enjoy kissing Sans’s soul a few hundred times, he needed something more efficient.

It was easy to draw his own soul out. He hadn’t looked at it since his death, other than to be sure it was still there, and it glimmered in a way it hadn’t in life, little stars lurking in the depths. Next to his, Sans’s soul looked more horrifying and pained. The core of his very being shouldn’t look like that.

There was no angle that could make the press of their souls comfortable, spikes jutting against his soul’s soft exterior. It stung, but he had endured far more for his brother’s sake, and this was nothing. He would have willingly stabbed his own core if it healed Sans of this.

He began to project, hoping the crystal wouldn’t block it. The love and the need to protect and all of the quiet moments they had stolen from their bloody world. Everything he could think of, he fed into his brother’s soul, every memory of drunken fumblings and early morning kisses before work, puns and pranks, the collar carefully latched around Sans’s neck and a second one carefully kept in a locked drawer, so that no one else would know that their ownership was mutual. Papyrus’s journey alongside Sans, shadowing him as he made his way to the Judgment Hall, refusing to leave him alone with only his grief enveloping him.

Initially, he thought the warmth starting to seep from Sans’s soul was just ambient heat from his own, but it soon grew to nearly scald him through his gloves. It wasn’t a painful heat, feeling more like an invigorating bath at the end of the day, like two pairs of bones slotted together to fit in a tiny bathtub. He could feel it turning the crystal brittle, and the surface of it cracked with the faint pressure of his hold.

 _Squeezing_ his brother’s soul would always be out of line, but he pressed more firmly, watching it splinter under his fingers, as if it was ice rather than crystal. Faint light began to reach through as he brushed particles away, and in only a few minutes, his brother’s soul was cleared. It looked pale and it didn’t have the glimmering lights that Papyrus’s soul bore, but it just needed time to recover.

The recovery of his soul definitely had an impact. What had taken two or three blows now crumpled in one, as he began work on Sans’s arm, starting at the shoulder. At this rate, he would be completely cleared of all of it soon.

“Uh, what the fuck am I walking in on?” He jolted at the sound of Undyne’s voice. It had felt like they had been in a world of their own; it was amazing that they had managed that much time without being disturbed by some other wandering spirit.

From her perspective it must have been bizarre at best: Sans half-naked still, Papyrus taking a hammer to his brother’s arm. Slowly evaporating chunks of crystal on the grass surrounding them, and more still bursting from Sans’s body. As much as he cherished Undyne as a friendly rival and military superior, he had never told her about his brother’s health condition. Technically Papyrus could have, as she was more trustworthy than most, but it was Sans’s business and no one else’s. Maybe she would have respected him less, if that was possible, and if it had gotten out somehow...

“You fuckin’ melted, you don’t get to talk about weird death shit,” Sans said, grinning up at her as much as he could, though his mouth was still crowded. Bits of it flaked off with the movement, which was promising.

“Oh shut up, it was heroic melting.” It was only a moment of levity before her face fell. “Papyrus... You can feel that shit, right? The world skipping back over and over again. Papyrus, I don’t know this last monster who’s trying to take down the human, but...they’re the last one left. Asgore’s gone.”

The hammer drooped from his fingers and he could feel Sans try to shift his arm just enough to touch his knee in the only comfort he could manage. He had been so focused on Sans that the flickers in the living world had seemed irrelevant. Asgore, dead? The nigh-immortal and powerful constant of the Underground, dead? Undyne had to be wrong somehow. If any of them could stand a chance, it would have been him.

“That can’t be true—”

“Papyrus, I saw my father figure get shanked by a fucking munchkin that stole his soul, I think I know what I’m talking about. Couldn’t find his ghost, but... maybe he doesn’t have one, if that kid has him. I hope he’ll show up once they pass through the barrier and let him go, but who knows?”

“What now?” It was the only thing he could think to say, maybe the only thing worth saying. It was childish to believe, even unconsciously, that everything would have been fixed had Asgore managed to kill the human. They weren’t going to all reform from scattered dust through the power of a single soul, and as long as the human willed it, there was nothing to keep them dead. It was inevitable that they would win, no matter if it took a thousand attempts that blurred time effortlessly.

“There’s nothing we can do, right?” Undyne said, laughing humorlessly. It hadn’t escaped his attention that she was still wearing her armor, though she could have cast it off now that she was dead. “I think I know where the survivors are hiding, so I guess...I’m going to go haunt them? Not much I can do to help, but at least I can know they’re okay.”

He knew there was no point in arguing with her. If she wanted to tear herself up over the people she had left behind, wasn’t it her right? And if they had an eternity, instead of fading away or reincarnating, she had plenty of time to self-flagellate and then move on. He had to believe she would forgive herself someday and find her way to the sea.

On the other hand, he was going to get them through the barrier. There was enough monster lore about the dead turning into stars that it had to be possible for spirits to pass through the barrier. Was that why this place wasn’t crowded with spirits bumping into each other? Had most of them managed to get out? Once Sans was recovered enough to appreciate the surface, they’d leave this pit behind, and good riddance to it!

“Goodbye, Undyne. It was an honor serving under your command.” Although there wasn’t much point to upholding ceremony now, he rose to his feet to salute her, posture perfectly straight. In the corner of his vision, he could see Sans’s hand flop against the grass, the best salute he could manage. ...Or just a random twitch of the arm, but Papyrus hoped it was a display of his grudging respect for Undyne.

“Oh, enough of that.” She slapped his pauldron and then, awkwardly, drew him into a one-armed hug that lasted for a few seconds. “I’ll see you two around, yeah?” From the way her eyes flickered upward before she walked away, she clearly knew that they would be heading to the Surface and away from her, but... He had the feeling he would find Undyne again, even if it took years of haunting beaches. He would see her again, someday.

“Whoever it is fighting that kid...they’ve got no chance. If they’ve already torn through Asgore and he wasn’t enough to make them give up, no one can do it.” Each word was a struggle for Sans to complete, but he seemed determined to get them out. From his battle, he knew that better than anyone else.

“There’s nothing we can do to help that monster, as we are. As much as I loathe complacency, it’s not our fight anymore.” No army of vengeful ghosts was going to swoop in and defeat this child. What were they meant to do, when they could barely interact with the living world and had been given nothing that could counteract powers over time itself?

He intended to keep cleaning Sans’s arms, but as Papyrus was examining his hand, the delicate phalanges overtaken, he spoke up. “Do my face next, will ya? I wanna see you.”

At least this part of the process was familiar to him. Carefully, he reached out to brush a crystal jutting out of his left socket. It definitely felt more fragile than things had been at the start. A light tap was enough to fracture it, and he helped Sans sit up and tilt his head so pieces of it could fall out.

  
He could still see traces of crystal clinging to the sides of his sockets, but it was clear enough for his eye light to flicker in. Sans stared up at Papyrus, and, though he must have been exhausted, the movement slow and shaking, he reached up a hand to touch Papyrus’s face. Not just his face, he realized—the eye socket that had been scarred for years and was now completely healed.

A change seemed to come over him, all at once. Papyrus had barely enough time to notice that the crystal in his other socket had reverted to one of those tumors he was so familiar with, before Sans raised his hand and drove his fingers through it, splattering them both. In any other context, it would have been gruesome, but Papyrus could think of nothing more wonderful than his brother regaining control over his own body.

The remaining infected magic began to dissolve and run off his body, leaving behind clean, unscarred bone, and he spat out a splash of crimson that had been the crystals lining his mouth just a second ago. It immediately began evaporating, though Papyrus barely had any time to look at it before Sans took his jaw in hand (a now mobile and unadorned hand) and kissed him with all the desperate longing that he must have felt since the moment of finding a tattered scarf in a pile of dust and snow. The scent of illness finally receded, and it was just Sans, smelling like smoke and sweat and bones as he crushed them together.

When they finally broke away from each other, panting heavily, he raised a hand to where his own skull had once been so horribly cracked. “Holy shit...” He looked down at his arms, and then at his still bared rib cage. Every scar and mark that he had once carried on his body, that Papyrus had memorized to caress and kiss a thousand times, had been erased. They had not been this unmarked since they were tiny babybones, if then.

“...Y’think I’ve got a chance in a beauty contest, now?”

“Sans, you idiot,” he scolded. “You’re as beautiful as you’ve always been.”

“Didn’t think this whole thing was real, even the soul thing,” Sans said faintly, as if to himself. “Like it was all something I was making up in my head. Until I saw you...”

“Yes, it’s real!” Now that Sans was restored, it was alright to _lightly_ smack him upside the head. “How dare you doubt me?!”

“Yeah, well. Wasn’t really in my right mind. I’ll make it up to you.” He followed it up with a lewd hand gesture, because of course he did.

As much as he wanted to stare at Sans’s naked bones forever, the sun was calling them. It took only a thought to conjure up a fresh shirt to (reluctantly) help him into. It was just a plain red t-shirt, identical to the ones he always wore, if more perfect: no torn seams, no frayed hem, absurdly soft and clean. Was that just the quality of afterlife-created objects, or did his mind insist on creating only the best for Sans? With Papyrus’s help, he rose to his feet.

“Are you ready?” From Sans’s snort, he seemed to find it a ridiculous question.

“Ready to leave this hellhole behind, yeah. Wish I could’ve got you up there alive, but...” His voice had gone thick with potential tears, and he swallowed heavily, reaching for Papyrus’s hand. They laced their fingers together. “Better than nothing? I know you can’t get the car you wanted, but at least there’s the sun.”

“There’s no point in regretting anymore, brother. I know that there’s aspects of the Surface we can’t enjoy like this, but there’s still so much to explore, and as long as I have you by my side, I can bear what we've lost.” He considered saying that perhaps it was better this way, because they were invulnerable to further human attack now, but from the way Sans was hesitantly grinning, he refused to ruin the fragile moment with a reminder of their deaths. “Shall we go?”

Needing only a single step, distance irrelevant now, they stepped through the Barrier together.

**Notes for the Chapter:**

> I decided it was better to finish this than to agonize for another few months over making it perfect. Frustrated but a little proud of myself for trying to make gross things romantic.  
> In the interest of making this slightly happier (?), this is the player character's final run, so the fellbros don't have their afterlife unceremoniously reset. Is that actually happier? I'm not sure.


End file.
